San Diego is a national leader in ADU construction, with more ADU permits issued per capita than almost any other US city. Its ADU Bonus Program lets owners build extra market-rate ADUs in exchange for deed-restricted affordable units, going well beyond state minimums.
Zoning & Size Requirements [1][2]
Yes, you can build an ADU in San Diego. A detached ADU can be up to 1,200 sq ft under current California and San Diego zoning rules.
| Allowed Zones | All residential zones; also allowed in some commercial mixed-use zones |
| Max Size (Detached) | 1,200 sq ft |
| Max Size (Attached) | 1,200 sq ft or 50% of primary dwelling |
| Max Size (JADU) | 500 sq ft |
| Max Height | 2 stories, with height set by the underlying base/overlay zone (state floor 16-18 ft) — no flat citywide 25 ft cap |
| Max Units | Base: 1 ADU + 1 JADU per single-family lot. ADU Bonus Program (reformed Aug 2025) caps total ADUs by lot size everywhere — 4 at 8,000 sq ft or less, 5 for 8,001-10,000 sq ft, 6 at 10,000 sq ft or more; bonus market-rate ADUs require a deed-restricted affordable ADU, and the program was eliminated in eight low-density RS zones (except High/Highest Resource Areas). Multifamily: up to 8 detached ADUs (SB 1211, capped at the number of existing units). |
Setback Requirements [1][2]
San Diego requires a rear setback of about 4 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is not required — you can rent it out without living on the property.
| Rear Setback | 4 ft |
| Side Setback | 4 ft |
| Front Setback | Per underlying zone |
| Parking Required | No parking required, except 1 off-street space in the Coastal Overlay Beach Impact Area outside a Transit Priority Area (standard ADU exemptions apply) |
| Owner Occupancy | Not required |
| Min Lot Size | No minimum lot size for JADUs |
Permit Process & Fees [3]
An ADU permit in San Diego typically costs $3,500-$12,000 and takes 60 days (often faster), through a ministerial, by-right review.
| Approval Process | Ministerial review; no discretionary approval needed |
| Review Timeline | 60 days (often faster) |
| Permit Fees | $3,500-$12,000 |
| Impact Fees | Waived for units under 750 sq ft |
| Plan Check | Standard plan check included |
| Pre-Approved Plans | Yes — companion unit program with pre-approved designs |
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Construction Costs [4][5]
Building an ADU in San Diego typically costs $120,000-$300,000 ($180-$350 per sq ft); a garage conversion runs $70,000-$160,000.
| Average Build Cost | $120,000-$300,000 |
| Cost per Sq Ft | $180-$350 |
| Garage Conversion | $70,000-$160,000 |
| Prefab ADU (Installed) | $90,000-$220,000 |
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
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Rental Income Potential [6][7]
A 2-bedroom ADU in San Diego rents for around $2,000-$2,800/mo, an estimated 7-11% annual return.
| Avg Rent (1 Bedroom) | $1,600-$2,200/mo |
| Avg Rent (2 Bedroom) | $2,000-$2,800/mo |
| Short-Term Rental | Not allowed for ADUs — minimum 31-consecutive-day lease (Information Bulletin 400); JADUs are barred from short-term rental |
| Est. Annual ROI | 7-11% annual return |
Explore Prefab ADU Options
Prefab ADUs can save 20-40% vs. traditional construction and cut build time in half.
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Recent Law Changes
What's Changed Recently
- Data accuracy correction (2026-06-28): updated per official city/state sources following a regulatory audit.
- SB 543 (effective Jan 1, 2026): ADU applications deemed approved if the city fails to act within 60 days
- AB 1154 (effective Jan 1, 2026): A locality may require owner-occupancy for a JADU only if it shares a bathroom with the primary dwelling; JADUs with their own bathroom are exempt (matching detached ADU rules)
- SB 1211 in effect (2025-2026): Up to 8 detached ADUs allowed on multifamily lots statewide
- City ADU Bonus Program (Municipal Code 141.0302) reformed in 2026: lot-size caps on total ADUs added; bonus market-rate ADUs require a deed-restricted affordable ADU; uncapped in Transit Priority Areas
- AB 1033 opt-in expanding (2026): more cities allowing separate sale of ADUs as condos
Tips for Building an ADU in San Diego
- San Diego's moderate build costs + solid rents = excellent ROI
- The online permit portal makes San Diego one of the easiest cities to get ADU approval
- Climate allows for cost-effective outdoor spaces that boost rental value
- Look into the companion unit pre-approved plans for fastest approval
ADU Builders in San Diego
Looking for an ADU builder in San Diego? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match San Diego homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- ADU/JADU Information Bulletin | City of San Diego Planning Department — Accessed 2026-02-24
- San Diego Municipal Code Ch. 14 — General Regulations Municipal Code — Accessed 2026-02-24
- Accessory Dwelling Units | City of San Diego Planning Planning Department — Accessed 2026-02-24
- Angi — ADU Construction Cost Data Market Data — Accessed 2026-02-24
- Angi — Local ADU Contractor Costs Market Data — Accessed 2026-02-24
- Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-02-24
- HUD Fair Market Rents Government Data — Accessed 2026-02-24
- California ADU Handbook — HCD Government Data — Accessed 2026-02-24
- California HCD — Accessory Dwelling Unit Handbook (updated March 2026) Government Data — Accessed 2026-06-28
- CA SB 543 (2025-2026) — Accessory dwelling units and junior accessory dwelling units (full bill text) Government Data — Accessed 2026-06-28
Frequently Asked Questions
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